IX] THE ENEMIES OF BUTTERFLIES 109 



experiments that certain lizards devour butterflies 

 freely, but that they do not exercise any discrimination 

 in the species which they attack. All are caught and 

 devoured indiscriminately, so that in spite of the fact 

 that such lizards are among the most serious enemies 

 of butterflies we cannot suppose them to play any part 

 in estabhshing a mimetic resemblance. 



III. Birds. The relations which exist between 

 butterflies and their bird enemies have for many years 

 been the subject of keen discussion. It is generally 

 recognised that if mimetic resemblances become estab- 

 lished through the agency of discriminating enemies 

 those enemies must be birds. Hence those interested 

 in the question of mimicry have for some years past 

 turned their attention to birds more than to the other 

 enemies of butterflies. That many birds systemati- 

 cally feed on butterflies is a fact that does not admit 

 of doubt. It is true that, as Mr Marshall points out 

 in the valuable paper in which he has summarised the 

 evidence^, observations of birds eating butterflies are 

 relatively scanty. Though, as he points out, this is 

 equally true for other groups of insects besides butter- 

 flies, bird attacks on butterflies, owing to the con- 

 spicuous nature of the victim, are much more likely to 

 attract attention than attacks on other groups. We 

 are still without much information as to the extent to 

 which birds destroy butterflies and as to whether they 

 shew any decided preference for certain species over 

 others. A careful examination of the contents of the 



1 Trans. Ent. Soc. Lond. 1909. 



